The once-a-day pill Edurant works by blocking the virus from reproducing. It is designed for use as part of a drug cocktail that reduce levels of HIV in the blood.

“Patients may respond differently to various HIV drugs or experience varied side effects. FDA’s approval of Edurant provides an additional treatment option for patients who are starting HIV therapy,” said Dr. Edward Cox, FDA’s director of antimicrobial products.

The FDA approved the drug based on a study of 1,368 patients showing it was as effective as Sustiva, an older HIV drug already on the market. After 48 weeks of study, 83 percent of patients taking Edurant had undetectable viral levels, compared with 80 percent of patients taking Sustiva.

The most common side effects with Edurant included depression, trouble sleeping, headache and rash.